1. Field of the Invention
The present invention relates to golf clubs. In particular, the present invention relates to a golf club head having an improved striking surface.
2. Description of the Related Art
Golf club heads come in many different forms and makes, such as wood- or metal-type, iron-type (including wedge-type club heads), utility- or specialty-type, and putter-type. Each of these styles has a prescribed function and make-up.
Iron-type and utility-type golf club heads generally include a front or striking face, a top line, and a sole. The front face interfaces with and strikes the golf ball. A plurality of grooves, sometimes referred to as “score lines,” is provided on the face to assist in imparting spin to the ball. The top line is generally configured to have a particular look to the golfer and to provide structural rigidity for the striking face. A portion of the face may have an area with a different type of surface treatment that extends fractionally beyond the score line extents. Some club heads have the surface treatment wrap onto the top line. The sole of the golf club is particularly important to the golf shot because it contacts and interacts with the ground during the swing.
In conventional sets of iron-type golf clubs, each club includes a shaft with a club head attached to one end and a grip attached to the other end. The club head includes a face for striking a golf ball. The angle between the face and a vertical plane is called the loft angle.
The United States Golf Association (USGA) publishes and maintains the Rules of Golf, which govern golf in the United States. Appendix II to the USGA Rules provides several limitations for golf clubs. For example, the width of a groove cannot exceed 0.035 inch, the depth of a groove cannot exceed 0.020 inch, and the surface roughness within the area where impact is intended must not exceed that of decorative sand-blasting or of fine milling. The Royal and Ancient Golf Club of St Andrews, which is the governing authority for the rules of golf outside the United States, provides similar limitations to golf club design.
U.S. Pat. No. 6,814,673 is directed to grooves for iron-type golf clubs.
Traditionally, the grooves that extend into the face of a golf club are generally parallel to a leading edge of the golf club. Oftentimes, a golfer's swing is imperfect and as a result, the golf club head is oriented either opened or closed when a golf ball is struck. As a result, the grooves do not contact the ball efficiently to impart backspin. Various groove orientations have been used in attempts to induce a corrective side spin on a ball that is struck with an imperfect swing. For example, U.S. Pat. Nos. 2,005,401; 5,505,450; and 6,348,010 all illustrate golf clubs with grooves that are angled relative to the leading edge of the golf club. Those references, however, fail to recognize that golfers often intentionally rotate the club about the shaft axis to create an opened or closed club head orientation. As a result, they fail to recognize the need for altering other attributes of the golf club head to achieve desired performance.